Comparing Different Cell Types

Here's where things get interesting – different types of cells have completely different structures depending on what job they need to do. Bacterial cells are the rebels of the cell world, doing things completely differently from animal and plant cells.

Bacterial cells are basically survival experts. They have flagella (like tiny propellers) to swim around, plasmids that carry extra genes (including antibiotic resistance – that's why superbugs are so dangerous!), and a tough cell wall for protection. What they don't have is a nucleus, mitochondria, or chloroplasts.

Plant cells are like animal cells with some serious upgrades. They've got everything animal cells have, plus a cell wall for structure, chloroplasts for photosynthesis, and a large vacuole filled with cell sap. Think of them as animal cells with solar panels and better storage!

The comparison table shows exactly what each cell type has and doesn't have. Animal cells are the basic model, plant cells are the eco-friendly version, and bacterial cells are the stripped-down, super-efficient model that's been around for billions of years.

Exam hack: Use the table to create memory tricks – bacteria are so tough they don't need mitochondria, but they do need flagella to escape danger!

Cell Specialisation and Bacteria

Here's the amazing bit – every cell in your body started exactly the same, but through differentiation, they became completely different specialists. A nerve cell looks nothing like a muscle cell, yet they both came from identical starting points!

Differentiation happens when cells switch certain genes on or off to become specialised. Root hair cells develop huge surface areas for absorbing water, whilst red blood cells lose their nucleus entirely to carry more oxygen. It's like students all starting in Year 7 but ending up with completely different careers!

Bacterial cells are reproduction speed demons – they can divide every 20 minutes under perfect conditions. That's how you can go from feeling fine to really ill so quickly when bacteria infect you. The numbers grow exponentially: 1 becomes 2, then 4, then 8, then 16, and so on.

When scientists want to study bacteria safely, they need uncontaminated cultures. This means flaming equipment, working near flames, opening dishes as little as possible, and incubating at exactly 25°C. Testing antibiotics involves placing filter papers soaked in different substances on bacterial cultures and measuring the clear zones where bacteria couldn't grow.

Real-world connection: Understanding bacterial reproduction helps explain why doctors are so concerned about antibiotic resistance – bacteria that survive treatment multiply incredibly quickly!

Plant and Animal Cell Details

Getting the specific parts of plant and animal cells sorted is essential for your GCSE – and once you know what each bit does, it all makes perfect sense. These are the eukaryotic cells you'll be tested on most often.

Both cell types share the same basic toolkit: a nucleus storing DNA (like the cell's hard drive), mitochondria producing energy (the power stations), ribosomes making proteins (tiny factories), cytoplasm where reactions happen (the workspace), and a cell membrane controlling entry and exit (the security guard).

Plant cells get some exclusive extras because they live a completely different lifestyle. Chloroplasts contain chlorophyll for photosynthesis (they make their own food!), the cell wall provides rigid structure (so plants can stand tall), and the large vacuole maintains shape and stores important substances.

Think about why plants need these extras – they can't move to find food like animals can, so they make their own. They can't run away from danger, so they need strong cell walls for protection.

Quick check: Remember that animal cells are more flexible and mobile, whilst plant cells are structured and self-sufficient!

Mitosis and Stem Cells

Ever wondered how a tiny cut on your finger heals itself? That's mitosis in action – the process where one parent cell becomes two identical daughter cells. Think of it as nature's photocopying machine!

Mitosis happens in six clear stages that you need to know. It starts with interphase, where the cell spends most of its time copying DNA. Then comes prophase (chromosomes become visible), metaphase (chromosomes line up in the middle), anaphase (chromosomes get pulled apart), telophase (new nuclei form), and finally cytokinesis (the cell actually splits in two).

Stem cells are like the ultimate shape-shifters – they can turn into any other type of cell your body needs. Scientists can use them to treat serious conditions like Parkinson's disease by growing new brain cells, or help people with spinal injuries by creating new bone cells. The process involves removing nuclei from egg cells and inserting patient DNA to create new stem cells.

Remember: Mitosis creates identical cells for growth and repair, whilst stem cells can become any specialised cell type your body needs.

Cell Structure Basics

Not all cells are created equal! Understanding the difference between prokaryotic and eukaryotic cells is crucial for your exams, and it's actually quite straightforward once you get the hang of it.

Eukaryotic cells (like animal and plant cells) have a proper nucleus that acts like the cell's control centre. Prokaryotic cells (bacteria) don't have a nucleus – their DNA just floats around freely in circular strands called nucleoids. Think of eukaryotes as having a proper office with separate rooms, whilst prokaryotes are more like open-plan studios.

When bacteria divide, it's called asexual reproduction because they're complete organisms on their own. When your skin cells divide, it's just called cell division because you're multicellular – made up of millions of different cells working together.

Every cell has some basic parts: the cell membrane controls what goes in and out, cytoplasm is where chemical reactions happen, and ribosomes make proteins. Animal and plant cells also have mitochondria (the powerhouses) and a nucleus containing genetic material.

Top tip: Remember that ALL cells have cytoplasm, ribosomes, and a cell membrane – these are the absolute essentials for life!